The principal objective of this application is to establish a new methodology for the early detection of abnormal lesions, whether pre-cancerous or cancerous, in breast imaging. Early detection is crucial to identifying lesions while they are still contained when the cure rate is near 100%. Existing mammography often does not identify lesions until significant growth has occurred. Because of the importance of the problem, there is research in alternative methods, including MRI, ultrasound, scintigraphy, and other methods. We propose here, a novel approach using biomagnetic sensors and targeted superparamagnetic nanoparticles. The sensor will detect and image lesions in-vivo to which these particles have bound by antibodies or angiogenesis agents after injection into the subject. We have demonstrated in Phase I of this program, that Superconducting Quantum Interference Devices (SQUID) are capable of detecting sub- nanograms of these nanoparticles. This methodology has advantages over existing mammography in the flexibility of nanoparticle choices to increase specificity through antibodies targeting cancer types such as HER-2, and angiogenesis agents targeting tumor microvascular structure. Nanoparticles will also be used to image sentinel cells for metastases. We will use phantoms and tissue preparations to characterize nanoparticles for sensitivity and image capabilities and animal studies to verify the methodology. We will further affirm imaging accuracy through the use of these nanoparticles as contrast agents in MRI studies in our animal studies. We anticipate that the detection of lesions by magnetic sensors will provide a lower false positive rate than mammograms and, more importantly, a higher true positive rate. [unreadable] [unreadable]